+ split file extension from descriptive text of file format to avoid that invalid translation breaks file dialog

+ add method to make image view unclosable for user
+ fix possible crash in MeshAlgorithm::GetMeshBorder
+ fix possible crash in MeshAlgorithm::ConnectLines

src/Gui/DlgOnlineHelpImp.cpp

@@ -23,7 +23,7 @@
 
 #include "PreCompiled.h"
 #ifndef _PreComp_
-# include <QMessageBox>
+# include <QMessageBox>
 # include <QDir>
 #endif
 
@@ -49,7 +49,7 @@ DlgOnlineHelpImp::DlgOnlineHelpImp( QWidget* parent )
 {
     this->setupUi(this);
 
-    prefStartPage->setFilter( tr("HTML files (*.html *.htm)") );
+    prefStartPage->setFilter(QString::fromLatin1("%1 (*.html *.htm)").arg(tr("HTML files")));
     if (prefStartPage->fileName().isEmpty()) {
         prefStartPage->setFileName(getStartpage());
     }
@@ -70,7 +70,7 @@ DlgOnlineHelpImp::~DlgOnlineHelpImp()
  */
 QString DlgOnlineHelpImp::getStartpage()
 {
-    QDir docdir = QDir(QString::fromUtf8(App::Application::getHelpDir().c_str()));
+    QDir docdir = QDir(QString::fromUtf8(App::Application::getHelpDir().c_str()));
     return docdir.absoluteFilePath(QString::fromUtf8("Start_Page.html"));
 }